Purpose Mobile phones increase the frequency and speed of communication. The most popular mobile application in Korea is KakaoTalk, one of the mobile instant messenger(MIM) services. Although studying mobile services such as SMS, SNS and SNG suggests drawing upon theories in marketing, consumer behavior, psychology to investigate their personal use, research on MIM is scarce. We designed this paper to fill this gap. More specifically, this study is focused on the relationships among consumers psychological variables related to purchase intention to emoticons in context of MIM. Design/methodology/approach Data was obtained from 310 KakaoTalk users in Korea via questionnaire. The data was analyzed by structural equation modeling in order to verify the relationship between variables in the model. Specifically, this study is designed to examine the structural relationships among perceived benefits, perceived risks, trust in messenger service, system quality, trust in platform, and emoticons purchase intention. Findings The findings of this study are as follow. First, perceived benefits and perceived risks had a significant impact on trust in MIM service(e.g. KakaoTalk). Specifically, while perceived benefits had a positive effect on trust in MIM service, perceived risks had a negative effect on trust in MIM service. Second, trust in messenger service also had a positive impact on system quality. Third, trust in messenger service and system quality had a positive effect on trust in platform(e.g. Kakao platform) directly. Lastly, trust in platform had a positive influence on emoticons purchase intention in KakaoTalk messenger.